In the past, permanent hose fittings have been mounted in a number of ways such as skiving the outer cover of a reinforced hose. In another approach, hose fittings are provided with sockets which thread over the cover of the hose with the threads cutting through the outer layer of the hose and directly engaging wire in reinforcement. An insert is later added to mate with an adjoining socket.
Both skiving and threadable engagement have disadvantages in that they remove or unnecessarily disturb the outer covering of the hose and are not necessarily easily adapted to simple, inexpensive and rapid manufacturing techniques or, for that matter, field attachment of permanent hose fittings.
In view of these considerations, hose fittings have been used for a number of years, wherein barbs are employed on the inner surface of hose gripping collars. These arrangements are not without difficulty. Sharply pointed barbs having a sturdy base have been used, but these barbs tend to move radially into the reinforcement upon crimping without deflecting either the reinforcement or barbs. Other barbs are configured for engaging the reinforcement but the barbs tend to deform in an uncontrolled manner upon crimping and thus result in hose fittings of varying quality.
In order to avoid the aforementioned drawbacks, the prior art includes fittings in which annular projections are provided with various geometries in order to accomplish adequate couplings. For example, the prior art includes fittings which have annular projections which bend in a controlled fashion; projections which are angled with respect to the inner surface of the sleeve from which they depend, and projections of various sizes and shapes.